From the documentation it appears (to me anyway) that the email sent after the end of a backup informing the specified recipients that the backup has completed successfully or with an error should be sent only at the end of a backup using the Front End url. The email texts and the recipient lists are configured in the "Front-end Backup" tab in Options. I am using the cli script akeeba-backup.cli invoked from a cron job on my local host machine. At the end of the backup, the success (or failure) emails specified in the "Front-end Backup"
Is this the intended behavior? if so, the documentation could be a bit clearer about that, and it would be clearer if the configuration of the email texts and recipients could be moved to a separate tab altogether - if not moved to somewhere in the configuration of profiles so each profile could be configured differently if necessary.
(This is probably not a big problem for most people, but if they, like I, take over the maintenance of a site previously configured by somebody else, tracking down where these emails get defined can take considerable time and effort.